In a double-blind trial 480 children undergoing adenotonsillectomy were given one of the following premedications: (a) droperidol only, (b) droperidol-phenoperidine, (c) papaveretum-hyoscine, (d) normal saline. In the doses used neither droperidol only nor droperidol-phenoperidine were associated with an improvement in pre-operative behaviour. Droperidol only showed a marked anti-emetic and anti-salivary effect. The addition of phenoperidine to droperidol produced some reduction of postoperative crying and restlessness together with postoperative amnesia but a tendency to postoperative pallor. Papaveretum-hyoscine showed some improvement in pre-operative behaviour but an excessive degree of salivary suppression and a tendency to repeated and persistent postoperative vomiting. In common with droperidol-phenoperidine there was a reduction in postoperative crying and restlessness and a tendency to amnesia. In view of its unexpectedly satisfactory performance in this trial there should be little ethical objection to using normal saline as a control in any future investigation of premedication in children.